LIVERPOOL, England—The most fearsome attacking trio in European soccer took three summers and $150 million to build. The pieces arrived in Liverpool one at a time, starting in 2015. First, it was the Brazilian forward Roberto Firmino. Then, Sadio Mané of Senegal. And finally, last June, Mohamed Salah of Egypt.

Those three have combined for 88 goals this season, making their bosses at Liverpool look like some of the shrewdest recruiting minds in the game. Which may be partially true. But as even Liverpool manager Jürgen Klopp admits, the real beauty of this unstoppable trident is that no one could foresee how well it would work.

Because for Salah, Firmino and Mané to power the club into Saturday’s Champions League final, Klopp had to do more than find a system to suit all three of them. He had to look deep inside each of their games and imagine whole new dimensions for them.

In Mané, a full-time center-forward until last season, he discovered a right-footed force to deploy on the left. In Firmino, a forward with a killer pass, he unearthed a tackling genius. And in Salah, who had previously flailed at Chelsea on the wing, he stumbled upon on a central finisher on the brink of the greatest hot streak in English soccer history.

“Nobody could know,” Klopp said of Salah’s explosion through the middle during his 43-goal campaign. “We learned it step by step.”

Salah is the constantly-on-fire breakout star of this season. On top of his record-setting 32 goals in the English Premier League, he has added 10 in 12 Champions League games. Only his opponent this weekend, Real Madrid’s Cristiano Ronaldo, has scored more in Europe. His pace, unpredictability and unbridled joy at playing the most advanced playground-style soccer in the world have raised the possibility of his becoming the first Ballon d’Or winner not named Ronaldo or Messi in over a decade.

“To have that composure when he’s running at speed, he’s incredible,” teammate Trent Alexander-Arnold said after Salah notched two goals and two assists in Liverpool’s semifinal victory over Roma.

Even more incredible is the fact that everyone remembers what happens when Salah isn’t deployed correctly. During a year and a half at Jose Mourinho’s Chelsea, he looked deeply mediocre. When the club offloaded him to Italy, no one missed him.

Surrounding him with Mané and Firmino, however, seemed to set him free. Which brings us to Klopp’s other key discovery in his Liverpool trident: Firmino’s secret defensive abilities.

Klopp urges his teams to win possession as high up the field as possible, keeping the pressure on opposing defenders before they can bring the ball out. That makes Klopp’s forwards his first line of resistance. It’s a demanding responsibility and, it turns out, the one thing that Salah isn’t particularly good at. The only direction he hates to sprint in is backwards.

Even when he does, he’s unusually clumsy in his efforts to win the ball back—he averaged more fouls per game than tackles in the league this season.

“He doesn’t love defending as he loves attacking but he’s still involved,” Klopp said. “Thank God [for] Roberto that he’s doing all of these things without thinking.”

Not only does Firmino chase, but he wins possession all the time—he led all Premier League forwards in tackles this year. In that way, Firmino has become the consummate Jurgen Klopp player: creative when he has the ball and willing to press relentlessly without it.

Nothing exemplified that better than the goal that killed off Manchester City for good in the Champions League quarterfinals. Firmino stepped up on City’s fullback in an innocuous part of the pitch, rushed him, and, moments later, forced a mistake. Firmino made off with the ball and ran clean through on goal to score. No complex buildup play. Not even a pass. Just a high press and tireless running. It’s no coincidence that Firmino has covered more ground than any forward or midfielder in the Champions League.

Throw Mané in the mix and there’s even more blistering pace on the field. By putting him on the left with his preferred right foot, Klopp gives him license to cut inside and charge directly into dangerous areas, where he can let his understanding with Salah and Firmino take over.

Firmino is “always looking for Mo. And Mo always wants to give the ball to me,” Mané said. “It’s something incredible for us.”

Three-pronged attacks have become fashionable in European soccer in recent years, with none more successful than Barcelona’s Messi-Luis Suarez-Neymar axis and Real Madrid’s Karim Benzema-Gareth Bale-Ronaldo band. But Liverpool’s version is slightly different in that it doesn’t have a clear senior partner. Firmino, Salah and Mane’s breakdown of Champions League goals this year is 10, 10, and 9 respectively. This trident also uses Firmino in more of a point-guard role, whereas the other two relied more on creative midfield play behind them.

But Liverpool’s was significantly cheaper than Real or Barca’s. And how the club pieced it together speaks to a larger evolution in the club’s buying philosophy.

When the Boston hedge-fund billionaire and Red Sox owner John W. Henry first acquired the club in 2010, he dreamed of importing the data-driven “Moneyball” approach that he had watched revolutionize baseball. But between soccer’s underdeveloped analytics and a raft of unpredictable factors in the English game, Liverpool struggled to adapt it. The result was a series of blunders in the transfer market.

Since Klopp’s arrival in 2015, the club has become more targeted in sourcing players that could potentially suit his system, even if it required tweaking their games. Plus, Liverpool was prepared to spend big to get them. It shelled out €42 million ($49.3 million) on Salah, which “seemed like a lot of euros at the time!” Henry wrote in an email.

But if Liverpool were to sell him this summer–which it has no plans to–Salah would be conceivably worth three times as much.

Discovering those efficiencies hasn’t solved all of Liverpool’s problems. The team is riddled with defensive frailties that slowed its domestic campaign over 38 games. But when the attack clicks the way it did in its 3-0 blitz of Manchester City in the Champions League quarterfinals or its 5-2 dismantling of Roma, that hardly seems to matter.

“I really think that the first half of the City game and maybe the first 50, 60 minutes of the Roma game was the most powerful football I have ever been a part of,” Klopp said. “We were always front-footed, we always tried to create. That’s how football should be.”